We Could Have Evolved the Placebo Effect to Save Energy

Illustration for article titled We Could Have Evolved the Placebo Effect to Save Energy

The placebo effect seems to make no sense: get mildly ill, take a dummy pill without knowing it's ineffective, and you'll recover in much the same way as someone taking real drugs. But new evidence suggests that we might have evolved the placebo effect to save energy.

New Scientist reports that new computer simulations seem to support an off-the-wall theory first put forward a decade ago: that sometimes for non-lethal illness, it pays for the immune system to not bother fighting. Because the immune system uses a lot of energy, so the theory goes, in days gone by it paid not to fight off infections if it could dangerously drain resources.

While that might sounds crazy, simulations published in Evolution and Human Behavior seem to back it up entirely. As New Scientist describes:

The model revealed that, in challenging environments, animals lived longer and sired more offspring if they endured infections without mounting an immune response. In more favorable environments, it was best for animals to mount an immune response and return to health as quickly as possible.

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Basically, then, the human body might not have shaken off a millenia-old adaptation that helped our bodies fight off infection selectively, depending on our environment and resources. Now we're all well-fed and full of energy, though, it seems the placebo effect may just remain as a quirk of nature. [Evolution and Human Behavior via New Scientist]

Image by Trif/Shutterstock

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DISCUSSION

im-thatoneguy3
im.thatoneguy

"take a dummy pill without knowing it's ineffective, and you'll recover in much the same way as someone taking real drugs"

Important disclaimer: just because the placebo effect makes you *feel* better doesn't mean you *are* better. In one study a group of patients were given a fake inhaler and another group a steroid (w/ a control group of course). The control group reported getting no better and their lung capacity didn't improve. Both the placebo and steroid patients reported similar improvement (steroid slightly better) but when it came to empirical performance the placebo actually didn't improve at all. So the Placebo only altered the * perception* of the condition not the actual condition itself. So that actually does fit into this study's conclusion that it's the body just letting us get on with our lives since there is no threat of death. Placebos work great for pain management and other *psychological* conditions. But you can't cure cancer with a placebo. You might feel better while having cancer but you can't cure it.

The mythology around placebos actually being wonder drugs are not merited. The placebo effect is almost exclusively limited to subjective tests not actual empirical wellness results.